The deposition of a benefit agent onto a fabric is well known in the art. In laundry applications typical "benefit agents" include fabric softeners and conditioners, soil release polymers, sunscreens; and the like. Deposition of a benefit agent is used, for example, in fabric treatment processes such as fabric softening to impart desirable properties to the fabric substrate.
Conventionally the deposition of the benefit agent may rely upon the attractive forces between the oppositely charged substrate and the benefit agent. Typically this requires the addition of benefit agents during the rinsing step of a treatment process so as to avoid adverse effects from other charged chemical species present in the treatment compositions. For example, cationic fabric conditioners are incompatible with anionic surfactants in laundry washing compositions.
Such adverse charge considerations can place severe limitations upon the inclusion of benefit agents in compositions where an active component thereof is of an opposite charge to that of the benefit agent. For example, cotton is negatively charged and thus requires a positively charged benefit agent in order for the benefit agent to be substantive to the cotton, i.e. to have an affinity for the cotton so as to absorb onto it. Often the substantivity of the benefit agent is reduced and/or the deposition rate of the material is reduced because of the presence of incompatible charged species in the compositions.
The deterging nature of laundry wash compositions also places severe limitations upon the inclusion of neutral but hydrophobic or oily benefit agents which are not effectively deposited in the presence of surfactant.
Alternatively, when deposition of a conventional benefit agent is effected by mechanisms that do not rely upon charge interaction but upon other non-covalent forces, for example soil release polymers, other problems may occur, namely where interaction of an anionic surfactant with the benefit agent can also make the material so negatively charged and/or soluble as to overcome the other attractive interactions.
Furthermore, there is frequently another complication in achieving optimum deposition of a benefit agent onto a fabric, in that, the need for solubility of the benefit agent in the medium used to treat the substrate is in principle, incompatible with the requirement for of the benefit agent to deposit/adsorb onto the substrate.
The present invention is directed towards materials for solving one or more of the above problems.
WO-A-98/00500 discloses detergent compositions comprising a peptide or protein deposition aid having a high affinity for fibres or a surface, and a benefit agent attached/adsorbed to the deposition aid. However, the peptide or protein is a relatively expensive material and the need still exists to find a more cost effective alternative material as a vehicle for depositing a benefit agent.
Our unpublished copending European Patent Application No. 98300292.4 discloses polysaccharide or oligosaccharide conjugates with an attached entity (e.g. a protein or an enzyme) having a molecular weight of at least 5,000. Although the poly/oligosaccharide is capable of binding to cellulose, there is no teaching of the molecular requirements for optimising the balance between water solubility and fabric affinity.
GB-A-948 678 discloses a process for dyeing and printing textiles using an aqueous preparation containing organic dyestuff residues linked by a covalent bond to high molecular weight polymers such as cellulose ethers, cellulose derivatives, starches, gums and other related naturally occurring polymers. Cellulose derivatives with a degree of substitution of 0.1 for carboxymethyl substituents are recited explicitly. However, these carboxymethyl groups and the dyestuff residues are not "benefit agent groups" within the sense intended herein.
U.S. Pat. No. 4 668 779 discloses a gel in the form of a complex between a metallic oxide and a semi-synthetic polygalactan. This is described for use in microbiological analysis. There is no disclosure of chemical bonding between a substance and the polysaccharide and certainly no substituent group which is in any way a benefit agent group for conferring a benefit to a fabric.
U.S. Pat. No. 5 160 641 and U.S. Pat. No. 5 540 850 disclose cellulose ether derivatives for use as anti-redeposition agents in fabric washing compositions. Substantially all of the saccharide rings are substituted. Furthermore, there is no mention of substituents which are themselves, benefit agent groups.
WO-A-95/30042 discloses a gel composition for use in the manufacture of treated fabrics. It comprises a cellulose based carrier with a solvent and a material for conferring a specialty finish, e.g. waterproofing, softening or anti-static effect. However, the specialty finish agent is not bonded to the cellulosic gel Further, there is no disclosure or suggestion of use during washing, rinsing or drying of fabric by a consumer.
WO-A-98/29528 discloses cellulose ethers in which some substituents are (poly)alkoxylated, analogues of the latter in which the (poly)alkoxylated groups are terminated with a cationic moiety in the form of a quaternary ammonium group, and cellulose ethers in which some substituents are carboxylic acids in the salt form (i.e. the materials are essentially carboxymethylcellulose variants). As defined by the general formulae in WO-A-98/29528, none of these molecules has regions of unsubstitution, as required by the present invention.
WO-A-99/14245 discloses laundry detergent compositions containing cellulosic based polymers to provide appearance and integrity benefits to fabrics. These polymers are cellulosic polymers in which the saccharide rings have pendant oxygen atoms to which substituents `R` can be hydrogen, lower alkyl or alkylene linkages terminated by carboxylic acid, ester or amide groups. Optionally, up to five alkyleneoxy groups may be interspersed between the groups are the respective oxygen atom. WO-A-99/14295 discloses structures analogous to those described in WO-A-99/14245 but in one alternative, the substituents `R` together with the oxygen on the saccharide ring, constitute pendant half-esters of certain dicarboxylic acids. As described in both of these documents, none of the pendant groups is a benefit agent group.
The present invention relates to materials for achieving initial solubility or dispersibility in the medium used to treat the fabric and effective deposition of one or more benefit-endowing groups thereon.